Field of the Invention
The present invention relates to an image forming apparatus, such as a copier and a printer, which functions to form an image on a recording material such as a sheet, and particularly to a developing assembly equipped in these apparatuses.
Description of the Related Art
A conventional developing assembly of the following configuration has been known. The conventional developing assembly is configured with a developing roller that bears a developer thereon and develops an electrostatic latent image formed on a photoreceptor, a feed roller for feeding the developer to the developing roller, a regulating member for regulating the layer thickness of the developer on the developing roller, and a developer container for storing the developer (see Japanese Patent Application Publication No. H6-301281).
The feed roller comes into contact with the developing roller at a certain penetration level and rotates in the same direction as the developing roller. A sponge roller in which a sponge layer is provided around a metal core bar is used as the feed roller. This feed roller is configured such that the developer is once introduced to the sponge layer and then the developer inside the sponge layer is discharged and fed to the developing roller by compressing the sponge layer by contact with the developing roller.
With increased users' awareness of the environment in recent years, it is crucial to use the developer of the developer container as much as possible. The conventional configuration described above, however, has a concern that the developer present in the vicinity of the core bar of the sponge layer of the feed roller remains in the sponge layer without being discharged from the sponge layer to the developing roller. In order to reduce the unused developer remaining in the sponge layer, the developer needs to be fed to the developing roller without using the sponge roller.
In other words, a developing assembly and an image forming apparatus that are capable of efficiently using the developer of the assembly are desired.